Owing to its exposure to bad weather and to the environment, it often happens that the gap is locally blocked by an accumulation of plant matter, ice, snow, pebbles or other foreign bodies or objects that can obstruct the flange(s) during the passage of the guide roller(s) or railway wheels. Such obstacles can lead to severe problems, such as damage to the rollers or wheels or, more seriously, to their derailment.
To avoid such problems, the gap all along the guide-rail or rolling rail network must be cleared regularly. However, such cleaning is time-consuming and expensive, and cannot be carried out during operation of the transport network and in particular that part of it using the rail concerned. Besides, even regular cleaning does not ensure the total cleanliness of gaps constantly exposed to bad weather, discarded garbage and attempted vandalism.
The forward protection element known as a “pebble guard” enables hard objects and ones above a certain size to be cleared from a rail and more generally a guiding or rolling track. Such protection, however, is quite useless against debris and small objects that may be present in one or other of the channels along the rail, which potentially endanger the guiding function and the vehicle's rollers or wheels.
There is thus a need for a gap that enables such objects to be passed over in total safety.